Product Overview
Hydraulic characteristics
- Reference conditions:
Upstream pressure = 8 bar
Downstream pressure
= 3 bar
Sizing procedure
Flow velocity is recommended to be kept within 3 to 6 feet per second
when calculating the correct pressure reducing valve size. This will
prevent noise in the pipes and rapid wear of appliances.
The correct diameter of the pressure reducing valve is taken from
graph 1 on the basis of the design flow rate taking into account an
ideal flow velocity in the valve body of between 3 and 6 f/s (blue band).
Example:
For 8 gpm, select the 3/4” size valve (see arrow on graph 1).
The pressure drop is taken from graph 2 also on the basis of where the
design flow rate intersects the curve for the valve size already selected
(the downstream pressure falls by an amount equal to the pressure
drop, with respect to the set pressure at no flow condition).
Example:
For 8 gpm the Dp = 7.3 psi (see arrow on graph 2).
∆p (bar)
0,5
1
0,2
0,1
1,5
0,3
0,4
0,6
0,8
1,2
0,9
0,7
∆p (m w.g.)
5
10
2
1
15
3
4
6
8
12
9
7
5351
1/2"
3/4"
5350
1/2"
3/4"
1"
1"
1 1/4"
1 1/2"
2"
0.45
5
V (m/s)
0.1
4
3
0.3
1 1/4"
(535074/5)
1”
1 1
/
4”1
/
2” 3
/
4”
1
2
5
0,2
10
20
20
50
100
Flow rate
(l/min) (m
3
/h)
200
5
10
1.5
V (f/s)
0.3
15
10
1
8
20
90
Flow rate
(/s)
(gpm)
30
40
10
5
2
1
0.9
5
50
60
70
1
2
0.5
0.2
0.1
0.05
3
4
6
1.5
0.3
0.4
2.5
80
3
4
0.150.5
2 0.6
3 0.9
6 1.8
5
4 1.2
1
/
2”1
2”
Graph 1 (Circulation speed)
48
103
20
10
150
28
35
62
117
90
68
5
10
2
1.5
20
3
15
7
1 in
1 1/4 in
3/4 in
1/2 in
FALL OFF PRESSURE
Reference values: Upstream pressure = 116 psi (800 kPa)
Downstream presssure = 43 psi (300 kPa)
14
∆
p (psi)
∆
p (kPa)
1 1/2 in
2 in
20
90
Flow rate
(/s)
(gpm)
30
40
10
5
2
1
0.9
5
50
60
70
1
2
0.5
0.2
0.1
0.05
3
4
6
1.5
0.3
0.4
2.5
80
3
4
Design Flow Rate
Size ½" ¾" 1" 1¼" 1½" 2"
gpm 4 to 7.3 7 to 12.5 10 to 19 17 to 34 24 to 44 37 to 70
Graph 2 (Pressure drop)